Recent changes to feature-requests

Metaflac & Replaygain: Add option for skipping files already containing replaygain tags

Kalle Kruse — Wed, 20 Mar 2013 18:49:27 -0000

For some users it is annoying that metaflac automatically re-processes which already contain replaygain information. See https://bugs.launchpad.net/ubuntu/+source/qtgain/+bug/718765 for example.

Other replaygain tools (like mp3gain) seem to skip such files - it would be nice to be able to optionally tell metaflac to behave accordingly.

WAV Regions & Markers Support

procty — Wed, 06 Mar 2013 02:28:19 -0000

I do a lot of audio work with hi-res WAV files. After projects are completed, I'd love to be able to compress them into FLAC files, but doing so destroys the embedded regions/markers from the WAVs. Would love to see that particular metadata be able to be automatically saved when compressing to FLAC.

multi-channel support for more than 8 channels

Nils Peters — Sat, 19 Jun 2010 15:07:14 -0000

Hi,

What is the reason that the multi-channel support in FLAC is currently limited to 8 channels?
Could that be extended to e.g. 32 or 64 channels ?

add FLAC__STREAM_DECODER_READ_STATUS_NO_DATA_AVAILABLE

Sulykos András — Mon, 28 Dec 2009 13:12:09 -0000

Hi,
I'd like to suggest a modification to existing libflac implementation. When you call the FLAC__stream_decoder_process_* functions there's no way
from returning it when for some reason you don't have the complete data for extracting the next metadata / audio frame.
For example, if the ReadCallback function reads the data during decoding from a buffer, but the buffer doesn't hold the whole data the decoder requires.
Then you give the data from the buffer to the decoder, but the ReadCallback handler will be called again, and you can choose only to return FLAC__STREAM_DECODER_READ_STATUS_ABORT which aborts the decoding process. If you were able to return something like FLAC__STREAM_DECODER_READ_STATUS_NO_DATA_AVAILABLE, then the process function would return, and you would be able to fill the buffer again
with the remaining data. I'm writing a Flac interface for my application and it can't be truly robust without it, because for some reason it cannot be guaranteed that a buffer from which the data is transferred to the decoder always holds enough data for a whole metadata block or audio frame.
Please include this option in the next release.
Thank you.

No support for adding ReplayGain tags to 96kHz files

Olli L — Mon, 06 Apr 2009 16:30:33 -0000

As summary says, metaflac does not support adding ReplayGain tags to high-resolution files. I would like to request support for this in the next release of flac.
(This is really a feature request, but I don't see somewhere to categorise this as one).

support for CAF (Core Audio Format) encoding/decoding

Josh Coalson — Wed, 07 Jan 2009 00:30:52 -0000

http://developer.apple.com/documentation/MusicAudio/Reference/CAFSpec/CAF_intro/chapter_1_section_1.html
or
http://developer.apple.com/documentation/MusicAudio/Reference/CAFSpec/CAFSpec.pdf

need suite of streams for compliance testing

Josh Coalson — Wed, 07 Jan 2009 00:23:52 -0000

flac needs a place where streams can be downloaded that exercise all the features of the format, to be used for decoder compliance testing.

NVidia CUDA enhancement

Jake — Fri, 19 Dec 2008 03:45:00 -0000

I think someone should look into the use of Nvidia's CUDA API as password crackers have claimed over 10x enhancement of speed, and a software called "TMPGEnc 4.0 XPress Video Encoder" claimed 446% performance enhancement. CUDA is a parallel graphics processor architecture. I think based on the nature of FLAC (compared to something like videos, which may depend on the previous frames to increase compression), it should be relatively easy to make it threadable to possible hundreds of cores, dramatically increase encoding/reencoding rates.

Preserve WAVE-FORMAT-EXTENSIBLE GUID

Hugh — Wed, 10 Dec 2008 17:54:57 -0000

When using the WAVEFORMATEXTENSIBLE format, the GUID identifying the type is not preserved.

For an example, the files in
http://halfbricking.com/Ambience/B-Format/
are in first-order Ambisonic B-Format, which has four channels (WXYZ), a special GUID identifying the format, and no channel mask (because the channels do not map to speaker positions).

The definition of the AMB format is at
http://dream.cs.bath.ac.uk/researchdev/wave-ex/bformat.html

More examples of AMB filetype can be downloaded from http://ambisonia.com/

Compressing these using flac -8 --channel-map=none: on decompress, the extensible type is reset to "rectangular quad" and speaker mask is set.

If the GUID is retained then the speaker mask will be ignored by Ambisonic decoders. Without the GUID the file is no longer a valid Ambisonic wav and cannot be decoded.

New metadata block for Lyrics

Simon — Sun, 31 Aug 2008 11:56:52 -0000

Unless I am mistaken... there seems no standard for embedding lyrics within flac files.

I've read through the format specification and I feel that a lyric metadata block would be a reasonable addition. There is a PICTURE metablock already defined, so why not a lyric block.

Obviously that would require adding support for it further down the line in applications... but once it's there people will use it.